I think some of the chronic ills of our society are rooted in the (incorrect) belief that solving any given problem is simply a matter of throwing $X at the problem.

"Donating time" is a deceptive phrase because it just sounds like you are paying out some currency other than money and that's it. "Donating time" encapsulates "building friendships, lifting up others, increasing love/unity in communities, gaining new perspectives" and more, unlike "donating money" which encapsulates none of them.